Arm extension for drilling foundation holes

ABSTRACT

An improved arm extension is provided which is mounted at one end to a carrier or the like, and which is capable of supporting an auger or other boring device at the other end. The arm extension is composed of one or more tubular sections coupled together to reach between the carrier and the site of the borehole, and preferably has a dog-leg configuration to elevate the engine mounted on its outer end to a suitable height above the borehole site.

United States Patent 1191 Farmer et al.

I45] July 17,1973

1 1 ARM EXTENSION FOR DRILLING FOUNDATION HOLES [75] Inventors: Glyen D.Farmer; J. C. Owens, both of Houston, Tex.

[73] Assignee: Farmer Foundation Company,

Houston, Tex.

[22] Filed: Dec. 15, 1971 [21] App]. No.: 208,215

[52] US. Cl 173/44, 173/22, 173/151 [51] Int. Cl E211) 3/04 [58] Fieldof Search ..l73/22-28, 43, 44, 151

[56] References Cited UNITED STATES PATENTS 1,663,833 3/1928 Genung173/151 X 2,791,399 5/1957 Curtis et al. 173/43 X 3,030,713 4/1962Hendrickson 173/43 X Primary Examiner-Ernest R. Purser Attorney DonaldH. Fidler and Edmund F. Bard [57] ABSTRACT An improved arm extension isprovided which is v mounted at one end to a carrier or the like, andwhich is capable of supporting an auger or other boring device at theother end. The arm extension is composed of one or more tubular sectionscoupled together to reach between the carrier and the site of' theborehole, and preferably has a'dog-l'eg configuration to elevate theengine mounted on its outer end to a suitable height above the boreholesite.

14 Claims, 7 Drawing Figures Patented July 17, 1973 2 Sheets-Sheet z ARMEXTENSION FOR DRILLING FOUNDATION HOLES BACKGROUND OF INVENTION Thisinvention relates to improved methods and apparatus for drillingboreholes in the earth and, more particularly, relates to improvedmethods and apparatus for drilling foundation holes for the installationof piling and other like foundation structures.

It is well known to construct foundations for buildings, bridges, wharfsand the like, by imbedding piles in the earth. It is further well knownthat small-diameter wooden piling of relatively short length can beinstalled by merely driving them into the earth.

It is impractical to drive large piling into the earth,

especially those formed of cast concrete. Accordingly, the process ofinstalling a large concrete piling involves drilling a hole of thedesired size and shape, and thereafter molding the pile in the hole.More particularly, a large auger is employed to drill the hole to itsdesired depth and diameter, and a steel casing is usually inserted forthe purpose of preventing'cave-ins as well as to provide a mold for theconcrete. Accordingly, after the auger is removed and replaced with anappropriate assembly of reinforcing rods, the casing may be filled withconcrete. I

It will be apparent that when concrete piling is to be installed in thismanner to support abridge or wharf or the like, most if not all of thepiles willnecessarily have to.be located in submerged land. Furthermore,in many instances the piling is installed at locations which may bespaced a considerable distance from the'bank of the river or other bodyof water. The other facet of the problem arises from the fact that thediameter of drill holes of this character may be 5-6 feet or evenlarger, and thus a hole of suchsize can only be drilled by equipmentwhich is very large and therefore very heavy.

It will be apparent that acrane composed of a carrier and boom isrequired for projects of this size. The carrier may be skid-mounted, orit may be acrawler-type or wheel-mounted unit of conventional design.The carrier is preferably provided with an extension arm for supportinga rotary table, and a boom for hoisting and supporting both theextension arm and the upper end of the shank of the auger or otherboring means which is rotatably mounted in the rotary table. An engineis also conventionally positioned on the outer end of the extension armfor revolving the rotary table which, in 7 turn, rotates the auger todrill the foundation hole.

Both the boom and the extension arm are pivotally connected to thecarrier, whereby the outer ends of these members can be moved arcuatelyup and down above the location of the drill hole. Thus, the rotary tableis usually positioned horizontally above the mouth of the drill hole bymeans of the extension arm, while the auger is suspended in the'drillhole from the end of a cable which hangs from the traveling end of theboom. In this way, the engine and rotarytable cause the auger to rotateto drill the hole, while the auger is lowered into the hole (or hoistedout) by means of the cable.

In many instances, the location of the hole to be drilled is much toofar from shore for thecarrier to be located'on dry land. Thus, thecarrier must bepositioned on a large floating platform which is broughtto and moored at the spot where the hole is to be drilled.

In other instances, the holes are to be drilled quite close to the bankor shore. Accordingly, the carrier may be positioned on dryzland withits arm extensionprotruding out over the water to the location where thehole isto be drilled.

A significant factor in the cost of drilling any foundation hole is thetime required to complete the project. Accordingly, it will readily beapparent that it is always a time-consuming operationto load thecarrieron a raft or other floating platform, and thereafter to maneuver theplatform to the location to'be drilled. In addition,

shore.

It will readily be apparent that it is-=the length of the armextensionwhich determinesthe maximum distance which the carrier or othersupporting means can be offsetfrom the site of thedrill hole. There aretwo factors limiting the length of 'the arm extension, however. Thefirstand obvious limitation isprovided by the fact that the totalweightof the armextension, engine,'rotary table, and (perhaps) theauger-cannot equal the weight of the tractor and boom, orelse'the-carrier will be unable'to stably support the arm extension. Thus,the total weight of the arm extension is a limitation on its overalllength.

Thesecond limitation arises, however, out of the fact that the armextension is subject to heavy stress because of the torquesupplied to itby the revolving auger.'Because-of this, it has been consideredessential to 7 provide the arm extension with aconsiderable amount -ofinternal 'bracingto'pre'ventits becoming deformed. The ill effects ofsuchstresses are greatly minimized in any arm extension by reducingits'length, of course. On the other hand, braces have weight, and if anarm extension is required to "be internally braced to. resist torque, itwill none the less be necessary to reduce the length of the armextension to compensate for the added weight of the bracing.

The various types of arm extensions presently available to the industryare truss-like structures which are heavily braced against the torquewhich results from rotation of the auger, and which are thereforerelatively short. Accordingly, it has been impossible to reach manydrill hole sites with arm extensions of the prior art, without takingelaborate and therefore expensive measures to support the carrier. Forexample, it has often been necessary to position the carrier on afloatingplatform or raft merely to-drill a foundation hole whichislocated only a relatively few feet off of the bank of a river.

The necessity of using a floating platform has, of course, substantiallyincreased the cost of building-piletype foundations at many submergedlocations, and this has constituted a significant disadvantage in themethods and apparatus of the-prior art. In some instances,

however, it has been impossible to move a floating plating a temporarycauseway.

These disadvantages of the prior art are overcome or substantiallyreduced with the present invention, however, and novel methods andapparatus are herewith provided for drilling a foundation hole at a muchgreater distance from the location of the carrier.

SUMMARY OF INVENTION In a particularly suitable form of the presentinvention, an arm extension is provided which is formed of a tubularmember preferably having a dog-leg configuration and a hollowcylindrical cross section. More specifically, the extension ispreferably formed of an assembly of sections. In such an embodiment, theaforementioned engine and rotary table are preferably borne by a sectionwhich is basically a length of hollow steel casing with closed ends, butwhich also preferably includes a short hollow section of easingangularly extending from the main section of casing in a mannersuggestive of the grip of a pistol. Both the rearward end (i.e., the endopposite the rotary table) of the main section of casing and the end ofthe so-called pistol grip portion are preferably provided with flangeshaving bolt holes at appropriate locations. Thus, the aforementionedsection of arm may be mounted on the carrier by means of another sectionof casing having flanges at both ends, this section being bolted eitherto the main casing portion of the engine-bearing section or to thepistol-grip section.

As hereinbefore stated, the ideal embodiment of the invention is atubular member having a dog-leg configuration and having means to bepivotally coupled to the carrier. In the case of drilling equipment ofconventional design, the truss-type arm extensions of the prior art arepreferably coupled to the carrier by means of a rocker arm or bolthorizontally interconnected with the carrier. It is desirable forpurposes of facilitating acceptance of the present invention that armextensions embodying the present invention be interchangeable withtruss-type arm extensions of the prior art. Accordingly, a pivot sectionis preferably provided which is cylindrical at one end, which ischisel-like at the other end, and which has a bearing-type sleeveportion fixedly secured along the line of convergence of the two facesof the chisel portions and adapted to receive the cylindrical bolt whichis used to couple the truss-type arm extension to the forward end of thecarrier. Thus, this sleeve portion is horizontally positioned when thepivot section is connected to the carrier, whereby the pivot sectionpivots about a horizontally positioned rocker pin mounted in thecarrier.

Since the arm extension which is the subject of the present invention ispreferably provided with a dog-leg configuration, the cylindrical end ofthe pivot section is preferably interconnected with one end of a shortdog-leg section having its other end coupled to one of the two flangedends of the engine-bearing section of the arm extension. Alternatively,and even preferably, it is desirable to employ an arm extension whichincorporates a dog-leg section sincethis will elevate the engine androtary table above the pivot point of the arm extension.

It is a feature of the present invention to employ at least a portion ofone of the cylindrical sections of the arm extension as a fuel tank tosupply the engine which drives the rotary table. It is further a featureto lengthen the arm extension, or to further elevate the engine, by

providing one or more intermediate sections of compatible size andconfiguration.

These and other features and advantages of the present invention will beapparent from the following detailed description, wherein reference ismade to the figtires of the accompanying drawings.

IN THE DRAWINGS FIG. I is a simplified pictorial representation of atractor carrying an arm extension embodying one form of the presentinvention.

FIG. 2 is a pictorial representation, partly in cross section, of aportion of the apparatus depicted in FIG. 1.

FIG. 3 is also a pictorial representation of another portion of theapparatus depicted in FIG. 1.

FIG. 4 is a simplified pictorial representation of apparatus of the typegenerally illustrated in FIG. 1, but wherein an arm extension is shownwhich is a different embodiment of the present invention.

FIG. 5 is a simplified pictorial representation of another embodiment ofthe present invention.

FIG. 6 is a simplified representation of an embodiment of the presentinvention constituting a modification of the apparatus depicted in FIG.5.

FIG. 7 is a pictorial representation of another embodiment of theapparatus depicted in FIG. 1.

DETAILED DESCRIPTION Referring now to FIG. 1, there may be seen asimplified representation of a mobile carrier 2 mounted in aconventional manner on a pair of endless tracks 6 and supporting a cab 3of conventional design. Thus, the carrier 2 may include provision (notdepicted) for winding in and paying out cables SA and 58 preferably fromthe end of a hoisting boom 4. Accordingly, the boom 4 is preferablypivotally mounted on the carrier 2, and, as will more clearly be seen inFIG. 4, further adapted to be arcuately movable up and down relative tothe area immediately in front of the carrier 2.

Referring again to FIG. 1, there may be seen an arm extension 7 composedof a long dog-leg section 8 connectedat one end to the carrier 2 by apivot section 9, and having its other end connected to a motor supportsection 12 by means of a fuel tank section 11. As may further be seen,the pivot section 9 may be rotatably connected at one end to a pivot pin10 or the like which is suitably mounted adjacent the cab 3 of thecarrier 2. The longer portion of the dog-leg section 8 may be seen to beconnected to the cylindrical end of the pivot section'9' by means of aflange 8A which is preferably bolted to the flange 9A of the pivotsection 9 in a conventional manner. The other shorter end of .he dog-legsection 8 may be seen to be coupled to one end of a fuel tank section 11which, in turn, is preferably coupled to the rearward end ofthe motorsupport section 12 opposite the rotary table 18 and table support 14.

As may be further seen in FIG. I, the motor support section 12 isadapted to suitably support an engine 13 so as to rotatably drive arotary table 18 of conventional design and adapted to slidably containan appropriate boring tool or the like. More particularly, the rotarytable 18 itself is preferably rotatably mounted in a table supportportion 14 of conventional design, and the upper end of the shankportion 15 of an anger 17 may be suspended from a suitable cable link 16fastened on the end of the cable 5A, whereby the lower bit portion ofthe auger 17 is permitted to engage and bore into the earth when therotary table 18 is revolved in the proper direction by the engine 13.The other depicted cable 58 may be seen to be attached to the engine 13to provide means for raising and lowering the arm extension 7.

Referring now to FIG. 2, there may be seen a more detailedrepresentation of the fuel tank section 11 depicted only generally inFIG. 1. Accordingly, the fuel tank section 11 may be seen to be composedof a relatively short length of cylindrical casing which is stoppered ateach end to form a container suitable tohold a quantity of gasoline orother liquid-type fuel 20. A fill pipe 22 of conventional design may bemounted in the upper portion of the fuel tank section 11 for receivingthe fuel when the tank section 11 is to be filled, and an exit pipe 21,which preferably extends to the bottom of the inside of the fuel tank11, is conventionally provided so that fuel 20 may be withdrawn by afuel pump (not depicted) in the engine 13.

Referring again to FIG. 2, it may be seenthat the fuel tank section 11'may be provided at one end with a conventional flange 25 which ispreferably bolted, in turn, to the flange 26 mounted on the shortportion of the dog-leg section 8. Similarly, the opposite end of thefuel tank section 11 is also preferably equipped with a similar flange23 which is preferably bolted to a similar flange 24 on the rearwardmotor supportsection 12.

Referring now to FIG. 3, there may be seen a more detailed pictorialview of the pivot section 9 depicted only generally in FIG. 1. Moreparticularly, the pivot section 9 may be seen to have a cylindrical endportion 27A adjacent the flange 9A and a chisel end portion 27B at itsother end having flat surfaces 28 and 29 which terminate at a hollowtube-like sleeve 19. Accordingly, the pivot section 9 may be pivotallycoupled to the cab 3 of the carrier 2 by a suitable pin 10 which ispreferably inserted slidably through the sleeve 19 and into bearingportions (not depicted) in appropriate 10- cations on the housing orframe portion of the cab 3. Thus, the arm extension 7 will be pivotallymovable by the cable 5B about the pivot pin 10 in a plane which isvertical with respect to the earth.

Referring now to FIG. 4, there may be seen a pictorial representation ofapparatus generally similar to the apparatus depicted in FIG. 1 buthaving an arm extension 7A which is substantially different in severalre-' spects. More particularly, the modified arm extension 7A may beconnected to the cab 3 by the same pivot section depicted in FIG. 1 andalso to include the same fuel tank section 11 and motor support section12 depicted in FIGS. 1 and 2. Instead of the dog-leg section 8illustrated in FIG. 1, however, there may preferably be provided arelatively long and straight hollow tubular arm section 30 which isinterconnected at one end to the pivot section 9 and at the other end tothe fuel tank section II. It is a particular feature of a long andstraight arm section 30 such as depicted in FIG. 4 that it is completelyhollow and thus is not equipped with any interior bracing of any type.Accordingly, although the long and straight arm section 30 issubstantially longer than any equivalent truss-type arm extension of theprior art, it is not only proportionally lighter in weight but alsocapable of maintaining and supporting the engine 13 and rotary table 18at a greater distance from the cab 3 than that heretofore obtainablewith the truss-type arm extensions heretofore in substantially universalemployment throughout this industry.

Referring now to FIG. 5, there may be seen another form of arm extension7B embodying the concepts of the present invention, and moreparticularly including a special arm section 41 having a cylindricalmotor support portion 42 adapted to support the engine 13, and apistol-grip portion 43 preferably provided with a conventional flange43A. Further, there is provided another flange 42A at the rearward endof the motor support portion 42. As will also be apparent in FIG. 5, theengine 13 may be removably attached to the top of the special armsection 41 by means of two pins 46 and 47 which may be slidably insertedthrough two pairs of coaxially arranged eye loops or brackets 44 and 45,respectively. As further depicted in FIG. 5, the arm extension 73preferably includes a short dog-leg arm section 38 having its shortportion connected to a flange 388 which, in turn, is bolted removably tothe flange 42A on the rearward end of the motor support portion 42 ofthe special arm section 41. The long arm portion of the dog-leg section38 is also provided with a similar flange 3813 which, in turn, is boltedto flange 42A.

In the embodiment of the invention depicted in FIG. 5, the pivot section9 is joined to the short dog-leg section 38 by means of a relativelyshort tubular member or cylindrical lengthening section 39, having aflange 39A at one end for interconnecting with flange 9A on the pivotsection 9, and having a flange 39B at the other end for interconnectingwith the flange 38A on the dog-leg section 38. The lengthening section39 may be omitted, of course, and flanges 38A and 9A may be bolteddirectly together. Alternatively, flanges 38A and 9A may be spaced evenfarther apart than as illustrated in FIG. 5 by the substitution of alengthening section even longer than as inferred from an examination ofthe apparatus depicted in FIG. 5. For example, the lengthening section39 may be replaced in the apparatus illustrated in FIG. 5 by the longcylindrical section 40 depicted in FIG. 6. l

I As will hereinafter be apparent to those with working. experience inthe art'of profitably drilling foundation holes of the type hereinbeforediscussed, there are many occasions when the condition of the earth issuch that the carrier 2 must be kept back an unacceptable distance fromthe site of the drill hole. For example, it may be that the drill holesitus is immediately off of a crumbling bank or a pier or wharf ofunstable condition. Irrespective of the reason, however, it will beessential to pitch the cable support portion 14 of the engine 13 as faras possible forward from the center of gravity of the carrier 2 in orderto reach the site of the drill hole with the auger I7. 7

There are other cases, of course, when it is not so essential toposition the auger 17 any unusual distance forward from the carrier 2,but for various reasons it is desirable to elevate the rotary table asmuch as possible while rotating the auger 17. For example, it isfrequently necessary to drill the foundation hole along a tilted axisrather than in a vertical'direction as is the usual case, and sometimesthe angle of tilt is such that the hole is aimed back under the carrier.Accordingly, and as indicated in FIG. 6, the arm extension 78 depictedin FIG. 5 may be altered to form the arm extension 7BB, and this may beaccomplished by removing the short dog-leg section 38 and short tubularsection 39, and by coupling the long tubular section 40 hereinbeforementioned to the pistol-grip extension or portion 43 of the special armsection 41. More particularly, the flange 408 at one end of the section40 may be bolted in a conventional manner to the flange 43A of thespecial arm section 41, and the flange 40A is then bolted to the flange9A of the pivot. section 9. Accordingly, the configuration of thespecial arm section 41 is such that, when the lengthening section 40 isinterconnected between the pivot mount section 9 and the branch 43 ofthe special arm section 41, this will elevate the position of the engine13 to a greater height than if the special arm section 41 is connectedas illustrated in FIG. 5.

In a further modification of the present invention, the arm extension 7depicted in FIG. 1 may be altered for certain purposes by replacing-thelong dog-leg section 8 with the short dog-leg section 38 and either theshort lengthening section 39 or the longer lengthening section 40, orboth. Thus, a version of the arm extension 7 may be selected which willprovide (within limits) an extremely useful variety of heights of therotary table 18 above the site of the drill hole. Further, it will beapparent that it is a relatively simple matter to assemble an varmextension 7 which is suitable to the hole to be drilled, whereas use ofthe truss-type arms of the prior art require that the hole be drilled ina manner and at a cost determined by the configuration of the drillingequipment.

Referring to FIG. 7, there may be seen a pictorial representation ofanother type of arm extension 7C, which may be characterized as amodified form of the arm extension 7 depicted in FIG. 1. Moreparticularly, however, the arm extension 7C may be seen to include apivot section 31 also having a chisel portion 34 composed of beveledsurfaces 35 and 36 converging to a tubular sleeve portion 33, ashereinbefore explained, and a cylindrical portion having a flange 32 andan eye bracket 37 preferably located on top of the pivot section. Thepiv'ot section 31 may be connected to the long end of a hollowdog-legsection 58 by interconnected flanges 32 and 58B, and a fuel tanksection 52 may conveniently be coupled to the other shorter portion ofthe dog-leg section 58 by flanges 58A and 528. Thus, a motor supportsection 60 is coupled by'flanges 52A and 60A to the other end of thefuel tank section 52.

As further illustrated in FIG. 7, the motor support section 60 may begenerally similar to the motor sup port section 12 depicted in FIG.1,except it is preferably provided with a rest or support bracket 61under the end opposite the flange60A to support it when the armextension 7C is lowered to the earth for some purpose such as to repairor to replace either of the cables A and 5B. In addition, two pairs ofeye brackets 48 and 49 may be included for the purpose of attaching anengine (not depicted).

Referring now to the fuel tank section 52, there may be included aconventional fill pipe 53 inserted in itsupper surface, a fuel outletline 50 which preferably extends to the bottom of the fuel tank 52 andwhich is adapted at its upper end to be interconnected with an engine(not depicted) on the motor support section 60. In addition, there maybe provided a fuel return pipe 51, whereby fuel from the engine may bere-routed to the fuel tank 52 to avoid the necessity of having todischarge it onto the ground. Finally, a suitable drain plug 54 may beinstalled in the lower portion of the fuel tank section 52.

Referring again to FIG. 7, and in particular to the dog-leg section 58depicted therein, it may be seen that another rest bracket 62 mayconveniently be attached under the end adjacent the flange 588 toprotect the extension 7C .if it is removed and deposited on the earth.In addition, it is desirable to provide a walkway 59 or the like, whichmay be composed of a series of steps leading to a catwalk running alongthe long and short legs of the dog-leg section 58 and extending past thefuel tank section 52 to the motor support section 60, whereby theoperator in the cab 3 may conveniently reach and service the engine 13if necessary. Accordingly, the operator of the carrier may service anyengine equipment mounted on the motor support section 60 without havingto stop the drilling operation and removing the auger 17 from the drillhole. Thus, a handrail 57 may also be conveniently installed along thelength of the dog-leg section 58.

Referring again to FIG. 7, it should be noted that a triangular brace 55is preferably installed to strengthen the joint between the long andshort legs of the dog-leg section 58. In addition, further support ispreferably included in the form of a strengthening patch 56 weldedacross the joint. Although only one such patch 56 is depicted in FIG. 7.it should be understood that another patch is provided on the oppositeside of the dog-leg 58. Furthermore, eye brackets 37 and '63 may beincluded for the purpose of providing means whereby the arm extension 7Cmay be lifted and carried about from one location to another.

Various other modifications and alternatives will be apparent which willbe within the scope of the present invention. Accordingly, it should beclearly understood that the methods and structures hereinbeforedescribed and illustrated in the accompanying drawings are exemplaryonly and are not intended as limitations on the scope of the invention.

What is claimed is:

1. In a drilling system for boring a foundation hole at an unstable orotherwise inaccessible drilling location and including i l a carrieradapted to be stationed at a stable location offset from said drillinglocation,

boring means for drilling said foundation hole,

engine means for rotating said boring means, and

pivot pin means horizontally positioned relative to said drillinglocation and detachably connected to said carrier,

the improvement in combination therewith comprising an arm extensionmeans for reaching from said carrier to said drilling location,including a hollow pivot member having a cylindrical configuration atone end and a pair of bevel surfaces converging and terminating at theother end to form a sleeve portion slidably receiving said pivot pin androtatably interconnecting said pivot member with said carrier,

a hollow tube-like engine carrying member detachably supporting andcarrying said engine means for driving said boring means, and

a hollow tube-like support member having one end coaxially anddetachably interconnected with said "pivot member for pivotal movementabout said pivot pin means and having its other end interconnected withsaid carrying member for supporting said engine and boring means in anoperating posture relative to said drilling location.

2. The improvement described in claim 1, wherein one end of said tubularsupport member joins with the other end thereof at an angle providingsaid arm extension with a generally dog-leg configuration.

3. The improvement described in claim 2, wherein said one end of saidtubular support member is longer than said other end thereof to therebyprovide said arm extension means with a dog-leg configuration.

4. The improvement described in claim 3, further.

comprising a cylindrical fuel tank member for containing a supply ofliquid fuel for said engine means and coaxially and detachablyinterconnected between said engine support means and said other shorterend of said tubular support member.

5. The improvement described in claim 4, further comprising a tubularlengthening member coaxially and detachably interconnected between saidcylindrical portion of said pivot member and said longer end of saidsupport member for positioning said carrying member at a higherelevation relative to said drilling location.

6. In a drilling system for boring a foundation hole at an unstable orotherwise inaccessible drilling location and including i a carrieradapted to bestationed at a stable location offset from said drillinglocation,

. boring means for drilling said foundation hole,

engine means for rotating said boring means, and pivot pin meanshorizontally positioned relative to said drilling location anddetachably connected to said carrier,

the improvement in combination therewith comprising an arm extensionmeans for reaching from said carrier to said drilling location,including a hollow pivot member having a cylindrical configuration atone end and a pair of bevel surfaces converging and terminating at theother end to form a sleeve portion slidably receiving said pivot pin androtatably interconnecting said pivot member with said carrier,

a hollow carrying member having a generally cylindrical body portion forcarrying said engine means in a position for drivingsaid boring meansand having a cylindrical branch portion obliquely diverging from saidbody portion at a location between the ends of said body portionthereof, and hollow tube-like support member having one end coaxiallyand detachably interconnected with said pivot member and having itsother end coaxially and detachably interconnected with said hollowcarrying member.

7. The improvement described. in claim 6, wherein said support member isaxially and detachably connected at its other end to the branch portionof said carrying member. 1

8. The improvement described in claim'6, wherein said support member isaxially and detachably connected at its other end to said body portionof said carrying member.

9. The improvement described in claim, 8, wherein said support member;has a dog-leg configuration with one end longer than its other end.

10. The improvement described in claim 9, wherein said support member isconnected at its shorter end to said longer end of said support memberis detachably fastened to said cylindrical portion of said pivot memherfor positioning said body portion of said carrying member at arelatively lower elevation above said drilling location.

13. An arm extension assembly for reaching a drilling location spacedlaterally from a base location, comprising a hollow pivot link memberhaving a cylindrical configuration atone end and converging bevelsurfaces at the other end terminating to form a sleeve pivotallysecurable at said base location, a hollow tube-like carryingmember-adapted to be disposed adjacent said drilling location, and ahollow tube-like support member having one end coaxially and detachablyinterconnected with said cylindrical end of said pivot link 'member andhaving its other end detachably and coaxially interconnected with saidcarrying member. 14. In a system for drilling a foundation hole andcomprising a carrier positionable at a base location, rotatableboringmeans for drilling a borehole in the earth at a drilling location spacedlaterally from said base location, an engine or the like for rotatingsaid boring means, and pivot pin means detachably linked in a horizontal'manner with said carrier at a position between said base and drillinglocations,

an improved arm assembly for interconnecting said engine and boringmeans with said carrier and pin means, including a hollow chisel-likelinking member having'a cylindrical configuration at one end and a pairof bevel surfaces at the other end converging and terminating at asleeve-like portion pivotally attachable to said pin means on saidcarrier means,

a hollow tube-like extension member having one end coaxially anddetachably locked to said cylindrical end of said linking member,

a hollow support member having a cylindrical body portion having twopair of aligned eye-like brackets detachably linkable with said enginemeans and having a cylindrical branch portion obliquely and diverginglyextending from said body portion from a point between the end of saidbody portion, and

' a hollow cylindrical angle member having a longer end portiondetachably and coaxially matable with the other end of said extensionmember and having a shorter end portion detachably and coaxially matablewith said body portion of said support member for spacing said enginemeans at a relatively farther distance from said base location and at arelatively shorter elevation above said drilling location,

said branch member also being detachably and coaxially matable with saidother end of said extension member for spacing said engine means at arelatively nearer distance from said base location and at a relativelyhigher elevation above said drilling location.

1. In a drilling system for boring a foundation hole at an unstable orotherwise inaccessible drilling location and including a carrier adaptedto be stationed at a stable location offset from said drilling location,boring means for drilling said foundation hole, engine means forrotating said boring means, and pivot pin means horizontally positionedrelative to said drilling location and detachably connected to saidcarrier, the improvement in combination therewith comprising an armextension means for reaching from said carrier to said drillinglocation, including a hollow pivot member having a cylindricalconfiguration at one end and a pair of bevel surfaces converging andterminating at the other end to form a sleeVe portion slidably receivingsaid pivot pin and rotatably interconnecting said pivot member with saidcarrier, a hollow tube-like engine carrying member detachably supportingand carrying said engine means for driving said boring means, and ahollow tube-like support member having one end coaxially and detachablyinterconnected with said pivot member for pivotal movement about saidpivot pin means and having its other end interconnected with saidcarrying member for supporting said engine and boring means in anoperating posture relative to said drilling location.
 2. The improvementdescribed in claim 1, wherein one end of said tubular support memberjoins with the other end thereof at an angle providing said armextension with a generally dog-leg configuration.
 3. The improvementdescribed in claim 2, wherein said one end of said tubular supportmember is longer than said other end thereof to thereby provide said armextension means with a dog-leg configuration.
 4. The improvementdescribed in claim 3, further comprising a cylindrical fuel tank memberfor containing a supply of liquid fuel for said engine means andcoaxially and detachably interconnected between said engine supportmeans and said other shorter end of said tubular support member.
 5. Theimprovement described in claim 4, further comprising a tubularlengthening member coaxially and detachably interconnected between saidcylindrical portion of said pivot member and said longer end of saidsupport member for positioning said carrying member at a higherelevation relative to said drilling location.
 6. In a drilling systemfor boring a foundation hole at an unstable or otherwise inaccessibledrilling location and including a carrier adapted to be stationed at astable location offset from said drilling location, boring means fordrilling said foundation hole, engine means for rotating said boringmeans, and pivot pin means horizontally positioned relative to saiddrilling location and detachably connected to said carrier, theimprovement in combination therewith comprising an arm extension meansfor reaching from said carrier to said drilling location, including ahollow pivot member having a cylindrical configuration at one end and apair of bevel surfaces converging and terminating at the other end toform a sleeve portion slidably receiving said pivot pin and rotatablyinterconnecting said pivot member with said carrier, a hollow carryingmember having a generally cylindrical body portion for carrying saidengine means in a position for driving said boring means and having acylindrical branch portion obliquely diverging from said body portion ata location between the ends of said body portion thereof, and a hollowtube-like support member having one end coaxially and detachablyinterconnected with said pivot member and having its other end coaxiallyand detachably interconnected with said hollow carrying member.
 7. Theimprovement described in claim 6, wherein said support member is axiallyand detachably connected at its other end to the branch portion of saidcarrying member.
 8. The improvement described in claim 6, wherein saidsupport member is axially and detachably connected at its other end tosaid body portion of said carrying member.
 9. The improvement describedin claim 8, wherein said support member has a dog-leg configuration withone end longer than its other end.
 10. The improvement described inclaim 9, wherein said support member is connected at its shorter end tosaid body portion of said carrying member and interconnected by itslonger end with said pivot member.
 11. The improvement described inclaim 10, further including a tubular lengthening member coaxially anddetachably fastened at one end to said cylindrical portion of said pivotmember and at the other end to said longer end of said support memberfor positioning said body portion of said carrying member at arelatively higher elevAtion above said drilling location.
 12. Theimprovement described in claim 10, wherein said longer end of saidsupport member is detachably fastened to said cylindrical portion ofsaid pivot member for positioning said body portion of said carryingmember at a relatively lower elevation above said drilling location. 13.An arm extension assembly for reaching a drilling location spacedlaterally from a base location, comprising a hollow pivot link memberhaving a cylindrical configuration at one end and converging bevelsurfaces at the other end terminating to form a sleeve pivotallysecurable at said base location, a hollow tube-like carrying memberadapted to be disposed adjacent said drilling location, and a hollowtube-like support member having one end coaxially and detachablyinterconnected with said cylindrical end of said pivot link member andhaving its other end detachably and coaxially interconnected with saidcarrying member.
 14. In a system for drilling a foundation hole andcomprising a carrier positionable at a base location, rotatable boringmeans for drilling a borehole in the earth at a drilling location spacedlaterally from said base location, an engine or the like for rotatingsaid boring means, and pivot pin means detachably linked in a horizontalmanner with said carrier at a position between said base and drillinglocations, an improved arm assembly for interconnecting said engine andboring means with said carrier and pin means, including a hollowchisel-like linking member having a cylindrical configuration at one endand a pair of bevel surfaces at the other end converging and terminatingat a sleeve-like portion pivotally attachable to said pin means on saidcarrier means, a hollow tube-like extension member having one endcoaxially and detachably locked to said cylindrical end of said linkingmember, a hollow support member having a cylindrical body portion havingtwo pair of aligned eye-like brackets detachably linkable with saidengine means and having a cylindrical branch portion obliquely anddivergingly extending from said body portion from a point between theend of said body portion, and a hollow cylindrical angle member having alonger end portion detachably and coaxially matable with the other endof said extension member and having a shorter end portion detachably andcoaxially matable with said body portion of said support member forspacing said engine means at a relatively farther distance from saidbase location and at a relatively shorter elevation above said drillinglocation, said branch member also being detachably and coaxially matablewith said other end of said extension member for spacing said enginemeans at a relatively nearer distance from said base location and at arelatively higher elevation above said drilling location.